I have recorded under a blanket, a blanket booth, a small 4x4x6 box and learned quickly what worked and what didn't. I knew a larger treated space meant better sound quality and a more comfortable space to record in.
My current studio is about 10x9x11 with all the walls being at different lengths and angles to each other. It is also treated with the necessary acoustic treatment to ensure a high quality sound is achieved. Not boomy but natural and bright. Over the years I have invested in mic/sound gear upgrades so you know your getting professional studio quality.
Microphones- Sennheiser MKH 416 Shotgun Microphone and a Neumann TLM-103
Mic Amplifier- Heritage Audio Elite Series HA-73 EQ
Compressor- Warm Audio WA-2A Leveling Amplifier
Interface- Apollo Twin MKII
Software- Adobe Audition
Studio Monitors- JBL 3MKII & Base
Monitoring Headphones- Sony Professional MDR7506